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  1. Teiid
  2. TEIID-5566

Outer join prevents dependent join creation

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Details

    • Bug
    • Resolution: Done
    • Major
    • 11.1.2, 12.0, 11.2.2
    • 11.0.1
    • Query Engine
    • None
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      Three databases are involved with joins that chain them together. A makedep option is given for the lean table of the second and third databases. If the second database is outer joined, no dependent join is created for it.

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      Three databases are involved with joins that chain them together. A makedep option is given for the lean table of the second and third databases. If the second database is outer joined, no dependent join is created for it.
    • Hide

      Use a preserve hint to prevent the manipulation of the join ordering. In this example it can be applied around the top level join:

      ... FROM /*+ preserve */ (meds_owner.compound ...) WHERE MEDS_OWNER... 
      Show
      Use a preserve hint to prevent the manipulation of the join ordering. In this example it can be applied around the top level join: ... FROM /*+ preserve */ (meds_owner.compound ...) WHERE MEDS_OWNER...

    Description

      This query:

      Edit: <I was asked to remove the query text from the top level description>
      The query is between three different databases chained together with joins (see plans).

      does not create a dependent join on the middle table. If you change the join to the middle table to inner, it does.

      Plans and debug plans for both cases are attached. As a note, an older version of Teiid that we are also using (9.3.4) always creates the dependent join. 11.0.1 and 10.2.3 do not create the dependent join if the table is outer joined.

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            rhn-engineering-shawkins Steven Hawkins
            mike.higgins@certara.com Mike Higgins (Inactive)
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              Created:
              Updated:
              Resolved: